Artificial-tooth cusp.



, 131113115. ARTIFICIAL TOOTH GUSP. APPLICATION FILED JUNE 13, 1910,

' Patented Ju1y11,1911.

7/70/1746 JTe/e.

, unrrn srnins rnrnnr ()FFICE.

THOMAS STEELE, 0F CGLUIVIIBU S, OHIO, ASSIGNOR TO THE COLUMBUS DENTALMANU- rncTcn-r'ne COMPANY, or. coLpMnns,

OHIO, A CORPORATION OF OHIO.

ARTIFICIAL-TOOTi-I CUSP Specification of Letters Patent.

Application filed June 13, 1910.

To all whom it may. concern:

Be it known that I, THOMAS S'rnnnn, a

citizen of the United States, residing at Go lumbus, in the county ofFranklin and State 5 of Ohio, have invented certain new and use- ,fulImprovements inArt-ificial-Tooth Cusps,

of which the following is a specification.

My' invention relates to improvements in which are set forth in theannexed specification and particularly pointed out in the claims.

The particular object of this invention is to provide an artificialtootlrcusp so formed thatall parts designed to come in contact withmetal can be ground to an accurate standard overcoming the variations ofshrinkage in the firing of the tooth and therebyremoving obstacles tointerchange- 0 ability.

K In the accompanying drawings-Figure l'is a bottom plan view of a molartooth cusp, Fig. 2 is a vertical section ofthe same, Fig. 3 is asectional view of an alternative form of cusp, Fig. 4 is a perspectiveview of the backing supporting the tongue and rib, Fig. 5 is a side viewof the backing employed in a Richmond crown, and, Fig. 6 is aperspective View of a denture showing the cusp and plate in position.

Similar reference characters indicate similarparts, in all'the drawings.

- molded of porcelain or other suitable material. A tubular recess gr isformed centrally' with the tooth cusp perpendicular to the. base E, anda slot B opens the recess perpendicularly and extends to a line in theplane of .the axis of the cusp from the bot-,

tom D of the recess, parallel to thegrinding surface C or the cusp andmeeting the 'E below its intersection Witli the labial aspectOf. Owingtothe shrinkage and unavoidable inequalities in the porcelain, the recessand slot cannot be minutely or accurately standardiz'edby the processesof molding and baking. My improved tooth is molded and fired with theslot and recess in such rudimentary form therein as can be formed by apattern. It being designed to locate the recess D with precisioncentrally in the tooth cusp and perpendicularly to the base I E thereof,and the slot B centrally and periF5 .pendicularly to the lingual aspectD there- 'wlien it is mechanically The tooth cusp O of a standard size,is

of, the faces E and E of the cusp are ground to perfectly flat surfacesrespectively to remove the numerous inequalities in the surfaces as thecusp came from the oven, centered and the recess D drilled in the trueplane of the cuspsaxis by a drill much smaller than the ultimatesta-ndard-size of said recess and the drill is positively actuated inthe plane of the axis without uidance from the rudimental recess formedwith the tooth cusp. This process of drillingis repeated with drillssuccessively larger than the first until a recess is formed of a certainstandard diameter, penetrating in every instance to an accuratelydetermined point at a standard distance from the cusp C and the lingualaspect D of the tooth cusp.

By methods of precision, the slot B lead ing into the recess throughoutits length and of less diameter than the recess, is corrected from therudimental slot formed with the tooth cusp, to a slot bi-laterallysymmetrical with the axis of the tooth cusp with walls parallel to theplane oithe mesial and distal faces E and E of the cusp.

The format-ion of the rudimentary slot and. recess in the cusp prior tobaking, is imperative for the reason that it is a practicableimpossibility to drill porcelain for commercial purposes without addingenormously to the expense. The drilling is, however, much simplified andrendered coinmercially possible where a recess is chipped or'reamed outby one or more drills, from a rudimentary recess as set forth.

F or the appropriate mounting of my i'm- 7 proved toot front in anyrequired declare, a tongue in the form of a cylindrical shell is formedwith a rib H and mounted on a backing F in the mathematical line of itslongitudinal axis, precise methods being here also. employed to theendthat the tongue shall exactly fill the recess in the tooth front, andtherib H, the slot B therein. What I claim, is- 1. An artificial toothcusp havinga fiat base ground at an angle divergent to the plane ofthetmasticating cusp and having a longitudinal, recess therein arrangedat an angle to the base of thecusp and a slot of less diameter than therecess opening the lattcr perpendicularly to the plane of grinding to apoint near'the lingual termination of the plane of grinding.

2. An artificial tooth cusp having a flat base it an angle divergent tnthe plane of 1 the ninsti0n'ting cusp from thciinguai aspect of thetooth, meeting :1 svzond plane in :1 line parallel to its lingual aspect:1 tubular T430055 of oncsizindiu'd size, pmpendicular to said flat baseand cun'rully disposed 1 ,UHHQID, a slot of less dmineier than therecess opening frmn ii1Q YCCOS vertically to the fiat surface to ,a.point near to the lin- 10 gual surface of the cusp. i

In testimony whereof I affix iny signature in presence oftwo Witnesses.

THOMAS STEELE.

Witnesses:

C. C SHEPHERD, J. V. CHAMPION.

